This invention relates to a spectrum analyzer, and more particularly to a spectrum selection device for a spectrum analyzer.
In present spectrum analyzer, the user generally selects a starting frequency and a frequency window of a spectrum based on experience or by first performing a spectrum analysis over a wide frequency band in order to identify a region for which more detail or resolution is of interest. Then, the operator switches to a narrow frequency band (or frequency window) of the wide frequency band to obtain more resolution. Unfortunately, after the user switches to a higher resolution mode, the spectrum may change and it may then be desireable to move the higher resolution analysis window to a new frequency band. This sometimes is not obvious to the user.
The object of the present invention is to provide a spectrum analyzer, such as a Fast Fourier Transform (FFT) based spectrum analyzer wherein the user can simultaneously view the wide and narrow (window) frequency bands so that the user is always aware of the best or more desireable frequency region to select for the higher resolution frequency band (frequency window).